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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
961

Efeito do ácido linoleico e catalese sobre o desenvolvimento e criotolerãncia de embriões bovinos produzidos in vitro na ausência de soro e baixa tensão de oxigênio / Mônica Ferreira Accorsi. -

Accorsi, Mônica Ferreira. January 2014 (has links)
Orientador: Silvia Helena Venturoli Perri / Coorientador: Gisele Zoccal Mingoti / Banca: Felipe Perecin / Banca: Flávia Lombardi Lopes / Banca: Caliê Castilho / Banca: Guilherme de Paula Nogueira / Resumo: O objetivo deste estudo foi avaliar os efeitos da suplementação do meio de cultivo com ácido linoleico e/ou catalase, em meio sem a adição de SFB, cultivados em atmosfera de baixa tensão de oxigênio sobre o desenvolvimento, qualidade e criotolerância de embriões bovinos. Em um grupo foi feita a suplementação com 100 μM de ácido linoleico (LA); 100UI de catalase (CAT) em um segundo, no terceiro grupo foram feitas as 2 suplementações (CAT+LA) e um quarto grupo sem suplementação (CONTROLE), durante todo o período de cultivo em atmosfera de 5%CO2, 7%O2 e 88%N2 em BAGS. As taxas de clivagem não diferiram (P>0,05) entre os grupos. Porém as taxas de produção de embriões em D7 e D8 diferiram (P<0,05), sendo que o controle obteve melhor resultado perante os 3 tratamentos e o grupo CAT+LA gerou a menor taxa de produção (30,7; 22,4; 19,8; 12,4%). Observou-se um atraso no desenvolvimento, sendo os blastocistos expandidos somente encontrados no D8. Na avaliação do conteúdo total de lipídios, houve uma redução significativa (P<0,05) nos 3 grupos tratados em relação ao controle. A medida dos níveis intracelulares de ROS não foi afetada nos 4 grupos (P>0,05). A quantidade de células totais foi significativamente menor (P<0,05) no grupo CAT+LA, e o grupo CAT foi o que apresentou maior porcentagem de células apoptóticas. Em relação à taxa de re-expansão às 24 horas (P<0,05), o grupo controle (50%) e o CAT (67,2%) apresentaram menores taxas que os grupos LA (71,7%) e o CAT+LA (76,7%). Às 48 horas, o grupo controle apresentou a menor taxa (35,7%), seguido pelo grupo CAT (47,5%). Já o grupo LA (56,5%) diferiu estatisticamente do controle mas não dos grupos CAT (47,5%) e CAT+LA (76,7%). O grupo CAT+LA diferiu estatisticamente dos grupos controle e CAT. Com base nestes resultados, embriões tratados com LA ou CAT+LA no cultivo in vitro, na ausêncio... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The most commonly recommended way to obtain more resistant in vitro embryos during the cryopreservation process is to change these embryos, whether through removal of fetal bovine serum (FBS), addition of different supplements to the culture medium or changes in oxygen tension in the production process. The objective of this study was to assess the effects of supplementation of the culture medium with linoleic acid and/or catalase in medium without the addition of FBS, in low tension oxygen atmosphere on development, quality and cryotolerance of bovine embryos. In one group, the medium was supplemented with 100 μm of linoleic acid (LA); the second was supplemented with 100UI of catalase (CAT), a third group was supplemented with both, CAT+LA and a fourth group received no supplementation (control), during the entire culture period in an atmosphere of 5% CO2, 7% O2 and N2 88% in BAGS. Cleavage rates did not differ (P>0.05) between groups (72.7; 74.1; 72.1; and 72.0%, respectively). However, embryo production rates in D7 and D8 were different (P<0.05), where the control had the highest blastocyst rate of the treatments and the CAT+LA group presented the lowest rate of production (30.7; 22.4; 19.8; 12.4%). Expanded blastocysts were only foundon D8, indicating a delay in development. There was a significant reduction (P<0.05) of total lipids in the 3 treated groups when compared to the control group. There was no difference in the intracellular levels of ROS between the 4 groups (P>0.05).Total cell number was significantly lower (P<0.05) in the CAT+ LA and the CAT group showed the highest percentage of apoptotic cells. Considering the re-expansion rates in 24 hours (P<0.05), the control group (50%) and the CAT group (67.2%) presented lower rates than the LA group (71.7%) and CAT+LA group (76.7%). At 48 hours, the control group showed the worst rate (35.7%) followed by the CAT group (47.5%)...(Complete abstract eletronic access below) / Doutor
962

An Examination of Cognitive and Behavioral Characteristics of Kainaiwa Children Diagnosed with Fetal Alcohol Syndrome

Pace, Deborah Faith 01 May 1997 (has links)
The present study examined the scores of 450 Kainaiwa children from Kindergarten to grade 3 on social, behavioral, cognitive and cultural measures. The subjects consisted of children in three different classification groups: Fetal Alcohol Syndrome (FAS), Special Education, and Regular Education. The purpose of the study was to examine group membership to determine whether or not children who were diagnosed as FAS presented unique intellectual, behavioral, social and cultural characteristics from those of their regular and special education peers. These results support the conclusion of previous research that FAS children differ significantly from their special and regular education peers. No statistically significant differences were found on cultural measures. This study provides useful information for future diagnosis and psychoeducational assessment for FAS children in early childhood.
963

The Association of Maternal Pregnancy Complications and Sudden Infant Death Syndrome

Myers, Patricia D 23 March 2003 (has links)
Sudden Infant Death Syndrome (SIDS) is the third leading cause of infant mortality between birth and the first year of life in the United States. Along with the identification of various maternal risk factors, the role of fetal hypoxia has been hypothesized to be one of many causal factors associated with SIDS. The purpose of this study was to develop a profile of the SIDS infant and assess whether six pregnancy complications consistent with fetal hypoxia were associated with the increased outcome of SIDS. The secondary data analysis of Florida linked birth to death certificate data specific to Hillsborough County and Duval County were analyzed retrospectively for the period of time between 1998 and 2000. Of the 86, 342 births, 69 SIDS cases were identified, 34 in Hillsborough County and 35 in Duval County. A majority of the infants were White males with an average age of death of 80 days. The Chi-Square test for Independence with Cramer's V, odds ratios and 95% confidence intervals were calculated to determine if an association existed between pregnancy complications, specific maternal risk factors and SIDS. Eclampsia was the only statistically significant prenatal complication found in this cohort (OR=4.67: 95% CI 1.49, 14.57). Maternal tobacco use (OR= 3.13: 95% CI 1.83, 5.36) and late initiation into prenatal care were also found to be significant in the SIDS cases, with the greatest risk occuring in women who did not receive prenatal care (OR=4.37: 95% CI 1.38, 13.89). These findings will assist with the development of a profile of infants who are at greater risk of dying of SIDS in Hillsborough County and Duval County as well as contribute to what is currently known about the association between fetal hypoxia and SIDS.
964

Foetal alcohol spectrum disorder: The development of guidelines to inform policy

Adebiyi, Babatope Oluwadamilare January 2019 (has links)
Philosophiae Doctor - PhD / Introduction: Maternal alcohol consumption during pregnancy can result to birth defects, which may be developmental, intellectual and physical. Fetal alcohol spectrum disorder (FASD) is a term used to describe an array of disorders related to alcohol consumption during pregnancy. FASD is a severe public health problem globally, with South Africa having the highest prevalence (29 to 290 per 1000 live births). What makes the FASD problem severe in the country is rife of maternal risk factors and widespread binge drinking during pregnancy. There is no policy specifically addressing FASD despite being pervasive in South Africa. Government programmes to prevent and manage FASD remain limited and fragmental across relevant departments. Herein, we aimed to conduct a multi-method study with a modified Delphi approach to developing a guideline to inform the development of a comprehensive and multi-sectoral policy for the prevention and management of FASD. Method and analysis: We used a modified version of the World Health Organization’s approach to guideline development in three phases. In phase 1, we conducted four different studies to design the initial guideline prototype. The studies include an in-depth interview with policymakers and a focus group with relevant service providers on policy requirements for FASD, a document review of policies on FASD and a scoping review of various interventions employed for the prevention and management of FASD. The second phase involved using the initially developed guideline prototype to engage with the local and international experts on FASD for improvement on the content. In the third phase, we refined the prototype using a modified Delphi approach. Framework method and content analysis were used to analyse the qualitative data while the Statistical Package for Social Science (SPSS) software was used to analyse the quantitative data.
965

The effects of intrauterine growth restriction on postnatal growth, arterial pressure and the vasculature

Louey, Samantha, 1977- January 2003 (has links)
Abstract not available
966

Maternal undernutrition and fetal blood pressure and the hypothalamo-pituitary adrenal axis in the late gestation fetal sheep

Edwards, Lisa J. January 2001 (has links) (PDF)
Includes bibliographical references (leaves 228-257). Aims to determine the impact of maternal undernutrition during late gestation and during the periconceptional and gestational periods on fetal growth, fetal blood pressure and the fetal hypothalamo-pituitary adrenal axis in the sheep.
967

Placental restriction and endocrine control of postnatal growth

De Blasio, Miles Jonathon January 2004 (has links)
Intrauterine Growth Restriction (IUGR) is evident in infants born with a reduced weight or length, and/or increased thinness for gestational age. IUGR is associated with altered postnatal growth and regulation, due to unknown mechanisms. Much clinical IUGR results from the reduced delivery of essential substrates (oxygen and nutrients) to the fetus, due to either maternal or placental limitations. Catch-up growth (accelerated rate of growth in absolute or fractional terms) occurs in the majority of IUGR infants, and returns an infant to their predetermined growth curve. IUGR is associated with increased risks of morbidity and mortality in the perinatal period, and with a reduced final adult stature and increased risk of adult onset diseases, particularly diabetes and cardiovascular disease. Catch-up growth after IUGR predicts improved health in terms of reduced hospital visits in infants and children, and an increased final adult stature but also predicts an increased risk of developing obesity, as well as diabetes and cardiovascular disease. The underlying mechanisms for catch-up growth may contribute to this range of outcomes in later life, but are poorly understood. Studies in IUGR infants have demonstrated increased absolute and/or fractional growth rates following birth, termed catch-up growth, in the presence of reduced or normal plasma concentrations of the thyroid hormones and major anabolic hormones (insulin and/or IGF-I). This suggests that increased sensitivity to, rather than increased production of insulin, IGF-I and thyroid hormone, causes catch-up growth following IUGR. We therefore hypothesised that placental restriction of fetal growth would reduce size at birth and increase postnatal growth and adiposity in association with increased metabolic sensitivity to insulin, IGFs and thyroid hormones. This study has shown that the placentally restricted (PR) lamb has a reduced size at birth in terms of soft and skeletal tissues, has increased rates of growth postnatally, and has increased adiposity by six weeks of age. We have also shown that PR of fetal growth in the sheep did not alter gestational age at delivery, but reduced survival rate. PR lambs demonstrated catch-up growth in most parameters by 30 days of age and increased adiposity at six weeks of age compared to the control lambs. Placental restriction increased insulin and IGF sensitivity of circulating free fatty acids, which in turn, predicts increased adiposity. Neonatal catch-up growth after fetal growth restriction was substantially predicted by both abundance of, and metabolic sensitivity to insulin, suggesting increased insulin action as an underlying cause. Catch-up growth occurs in the neonate despite reduced concentrations of fasting plasma IGFs, along with increased IGF sensitivity of free fatty acid metabolism and adiposity. Plasma TH concentrations predicted growth of soft and skeletal tissue in lambs during early postnatal life, particularly in those undergoing catch-up growth following PR. Therefore neonatal catch-up growth after IUGR is associated with increased sensitivity to both insulin and IGFs, particularly of circulating free fatty acids, and appears to occur to the extent allowed by the prevailing abundance of these hormones and of thyroid hormones. If this altered endocrine state persists, increased adiposity and its subsequent amplification may contribute to the development of obesity, and related adverse metabolic and cardiovascular outcomes in adult life. / Thesis (Ph.D.)--School of Molecular and Biomedical Science, 2004.
968

Role of hypothalamic pituitary adrenal axis in prenatal programming of adult disease.

Grover, Sanita January 2008 (has links)
Low birth weight is associated with an increased risk of impaired glucose tolerance and type 2 diabetes and with signs of increased hypothalamic pituitary adrenal axis activity in later life (1, 2). Low birth usually weight reflects a reduction in fetal growth, which largely depends on an adequate supply of nutrients and oxygen. Variations in supply modify the metabolic and neuroendocrine characteristics of the fetus, which in turn modulate the pattern of functional development as well as growth (3). An adverse fetal environment, evident as low birth weight, is therefore proposed to alter functional development with long term effects for the function and risk of disease in the individual later in life (4, 5). Increased HPAA impairs metabolic homeostasis and could therefore mediate effect of prenatal challenge on later metabolic control (6). It was therefore hypothesised that restriction of fetal growth, increases circulating cortisol and/or alters sensitivity to cortisol, which increases fasting blood glucose, and impairs glucose tolerance in the young adult. Large litter size in the guinea pig is characterised by reduced placental and fetal growth, reduced size at birth and insulin resistance in offspring in later life, providing a suitable model to test this hypothesis. Spontaneous restriction of fetal growth in the guinea pig, evident as small size at birth, was associated with increased salivary cortisol, in both sexes but at different stages of postnatal life. In males, salivary cortisol was increased with small size at birth in early and adult life, but reduced later with ageing. In females however, salivary cortisol was increased in juveniles and in aged adults, possibly reflecting the impact of the oestrus cycle on cortisol production in mature cycling females. Altered activity of the HPGA, which can influence that of the HPAA, has also been reported to be programmed by prenatal restriction. In the guinea pig, salivary testosterone in males increased with age and small size at birth in juveniles, young and aged adults. In females, salivary progesterone increased with age up to 300 days, and decreased with size at birth in the young guinea pig. Although testosterone inhibits HPAA activity, in males, mean salivary cortisol correlated positively with mean salivary testosterone at 100 and 300 days of age. In contrast, progesterone may enhance HPAA activity, and consistent with this, in females, mean salivary progesterone correlated with mean salivary cortisol at 400 days of age. Therefore, salivary testosterone in the male and salivary progesterone in the female guinea pig changes with maturation and has previously reported in this or other species, but small size at birth increases salivary testosterone in males with modest effects in early life in females. This together with the unexpected positive associations of salivary cortisol with testosterone in males, suggests that programming of the HPAA makes little contribution to that of the HPAA as indicated by salivary cortisol. Here we show that low birth weight is associated with increased fasting blood glucose and impaired glucose tolerance in both male and female young adult guinea pigs aged 100 days. Fasting and mean (during IVGTT) plasma cortisol was reduced in low birth weight female adult guinea pigs, and is not vary with size at birth at this age in males. This suggests that circulating cortisol does not contribute to the impaired glycaemia associated with small size at birth in the guinea pig. Glucose tolerance was increasingly impaired in males but not females, as mean plasma cortisol increased. This is consistent with cortisol impairing glycaemia in the guinea pig as in other species, in males at least. To assess the role of cortisol in prentally programmed impairment of glycaemia directly, metyrapone or vehicle containing 24% ethanol was administered to young adult guinea pigs for 3 days. Treatment with the latter impaired fasting blood glucose and glucose tolerance in females and the latter in males compared to a previous IVGTT and this was exacerbated in low birth weight females. Metyrapone prevented this impairment of fasting glycaemia and glucose tolerance in the low birth weight adult female guinea pig and in the male guinea pig regardless of birth weight class. Neither vehicle or metyrapone altered plasma cortisol, before or during a second IVGTT. Limited numbers of animals, particularly females, limited this study however and additional investigation is required. Nevertheless this shows for the first time that inhibition of glucocorticoid synthesis in the guinea pig improves glucose control. Furthermore this suggests that the low birth weight guinea pig may be more sensitive to cortisol, have increased cortisol synthesis or reduced inactivation of cortisol in peripheral tissues, leading to increased local cortisol action. In conclusion, alterations in peripheral HPAA activity in the guinea pig due to restricted fetal growth may contribute to their prenatally programmed development of impaired glucose tolerance as young adults, but the extent of that contribution may vary with age and gender. / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2008
969

Immunological aspects of maternal-foetal interactions in mice

Arvola, Marie January 2001 (has links)
<p>Mammalian pregnancy is an immunological paradox. The foetus, which expresses both paternal and maternal cell-surface molecules, has to be protected from rejection by the maternal immune system. At the same time, the mother has to have an efficient immune defence and must provide her offspring with antibodies.</p><p>The first part of this thesis investigates some of the mechanisms involved in the foetal avoidance of maternal rejection reactions. Placental absence of MHC class II expression, as well as a bias for Th2-cytokines at the maternal-foetal interface are suggested to be important for foetal survival. The results showed that placental MHC class II expression cannot be induced <i>in vivo</i>. Transfections of trophoblast cells with MHC class II genes, however, resulted in detectable MHC class II cell-surface expression, indicating that a post-transcriptional block does not exist in these cells.</p><p>By using IL-4- and IL-10-double deficient mice, it was shown that neither maternal nor foetal expression of these cytokines were crucial for completion of allogeneic pregnancy.</p><p>In the second part of the thesis, the effect of transmission of immunoglobulin G (IgG) from the mother to the offspring was studied. It was observed that viable maternal Ig-secreting cells occasionally infiltrated the B cell-deficient offspring and remained functional for long periods. In this study "green fluorescent mice" were used as a tool. Furthermore, neonatal ingestion of wild type milk increased the survival of adoptively transferred B-lineage cells in B cell-deficient mice, suggesting that suckling of IgG-containing milk could be used to facilitate B cell-reconstitution in B cell-deficient mice. Finally, results from studies on normal mice showed that absence of maternal IgG-transmission during their neonatal development resulted in elevated serum-IgG production, as well as enhanced immune reactions upon immunisations in adult life. This showed that maternal IgG can have long-term immunoregulatory effects in the offspring.</p>
970

Hormonal Regulation of the Human CYP27A1 and CYP7B1 Genes

Tang, Wanjin January 2007 (has links)
<p>CYP27A1 and CYP7B1 are widely expressed in various human tissues and are two key enzymes involved in the pathways for conversion of cholesterol to bile acids. Also, CYP27A1 is involved in bioactivation of vitamin D3 and CYP7B1 plays a role in 7alpha-hydroxylation of dehydroepiandrosterone and other steroids. Both enzymes have been reported to be relevant to prostate cell proliferation. The current study examines the hormonal regulation of CYP27A1 and CYP7B1.</p><p>CYP7B1 was shown to be regulated by estrogens and androgens in human embryonic kidney HEK293 and prostate cancer LNCaP cells. Quantitation of CYP7B1 mRNA in adult and fetal human tissues showed markedly higher CYP7B1 mRNA levels in fetal tissues compared with the corresponding adult ones, except in the liver. This indicates a tissue-specific, developmental regulation of CYP7B1 and suggests an important function for this enzyme in fetal life. CYP7B1 regulation by estrogens may be of importance in fetal development and in other processes where CYP7B1 is involved, including cholesterol homeostasis, cellular proliferation, and CNS function. The regulation of CYP7B1 by sex hormones also suggests an important role for CYP7B1 in balancing prostate hormone levels in human cells. </p><p>Results show that CYP27A1 can be regulated by dexamethasone, growth hormone, IGF-1, PMA, estrogens and androgens in liver-derived HepG2 cells. Dexamethasone, growth hormone and IGF-1 stimulated the promoter and endogenous activity of CYP27A1, whereas thyroid hormones and PMA inhibited CYP27A1. The regulatory effects of estrogens and androgens are different depending on the cell types. Thus, the results imply that human CYP27A1 gene is a target for estrogens and androgens, and the expression of CYP27A1 may be affected by endogenous sex hormones and pharmacological compounds with estrogenic or androgenic effects. </p><p>The mechanism for the dexamethasone-induced effect on the human CYP27A1 promoter was examined. A GRE was identified important for GR-mediated regulation of CYP27A1 transcriptional activity. </p>

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